Pulmonary Hypertension Hatlan ALhatlan

Outlines Overview Natural history Modalities X-ray CT Echocardiography Summary Sources

Overview Normal pulmonary circulation : 1.High-flow with low-resistance circuit capable of accommodating the entire right ventricular output at one fifth the pressure of the systemic circulation level. 2.The right ventricle functions primarily as a flow- generator pump and is particularly sensitive to increases in its afterload. 3.Increased pulmonary artery pressure and pulmonary vascular resistance characterize pulmonary hypertension.

Pulmonary Hypertension Pulmonary hypertension. Chest radiograph in a patient with secondary pulmonary hypertension reveals enlarged pulmonary arteries. This patient was found to have an atrial septal defect.

Natural History Resting mean pulmonary arterial pressure of 25 mmHg or more, or >30 mmHg with exercise. Primary (Idiopathic) or secondary (many known causes). Dyspnea (during exercise), edema, and abdominal distention (signs of elevated right side pressure)

Modalities used X-ray CT Echocardiography MRI Nuclear imaging Angiograhy

X-Ray

Plain X-ray By time of diagnosis, 90% of patients have already abnormalities. (low sensitivity and specificity) Findings: 1.Elevated apex due to right ventricular hypertrophy (a decrease in retrosternal area) 2.Enlarged right atrium (opacity over right retrosternal space). 3.Enlarged pulmonary arteries.

Plain X-ray 4.Right hilar enlargement, can be on both sides. 5.Pruning of peripheral pulmonary vessels. The X-ray shows gross enlargement of the cardiac silhouette. The right border extends far to the right indicating gross right atrial enlargement.The right atrial enlargement may be due to severe pulmonary hypertension and right ventricular failure.

Plain X-ray Chest radiograph reveals enlargement of the pulmonary vasculature and the central pulmonary arteries (arrows). Secondry hypertension By atrial septal defect.

Plain X-ray PA film of chest in a patient with primary pulmonary HTN showing right heart and main pulmonary with its right and left branches. Lateral CXR of the same patient, showing enlarged pulmonary artery.

Plain X-ray Cardiomegaly and prominent bilateral pulmonary arteries in the hilar areas can be seen in the posteroanterior chest radiograph from a patient with idiopathic pulmonary arterial hypertension. The lateral view also reveals enlarged pulmonary arteries and cardiomegaly without any evidence of congestive heart failure.

Computed Tomography

CT is good, noninvasive, used to confirm presence of pulmonary hypertension. CT pulmonary angiogram (CTPA) is useful in delineating the anatomic detail of the pulmonary vasculature. CTPA is the best method for demonstrating emboli. Contrast-enhanced images may show intraluminal abnormalities in the arteries and veins and can detect emboli if it’s large. CT pulmonary angiogram demonstrates clots in both the right and left main pulmonary arteries.

Computed Tomography Findings in CT : Extra cardiac vascular signs: Enlarged pulmonary trunk >29 mm diameter is often used as a general predictive cut-off Enlarged pulmonary arteries Mural calcification in central pulmonary arteries Evidence of previous pulmonary emboli Cardiac signs : Right ventricular hypertrophy: defined as wall thickness of more than 4 mm Straightening or bowing (towards the left ventricle) of the interventricular septum Right ventricular dilatation Decreased right ventricular ejection fraction Dilatation of the inferior vena cava and hepatic veins Pericardial effusion Parenchymal signs: Centrilobular ground-glass nodules (Cholesterol granuloma). Neovascularity: tiny serpiginous intrapulmonary vessels that often emerge from centrilobular arterioles.

CT of Idiopathic Pulmonary HTN Axial contrast-enhanced CT scan obtained at initial presentation shows central pulmonary artery dilatation with aneurysmal enlargement of the left lower lobe pulmonary artery (*) but no evidence of intraluminal thrombi. Axial contrast-enhanced CT scan obtained 2 years later shows wall-adherent apposition thrombi(a complication) (arrowheads) with recanalization (arrows) in the pulmonary artery trunk and the right main pulmonary artery. The left lower lobe pulmonary artery (*) remains enlarged.

CT of Idiopathic Pulmonary HTN Spiral CT scan in a patient with pulmonary hypertension reveals enlarged pulmonary arteries and an absence of thrombosis.

Computed Tomography High-resolution CT (HRCT) scanning of the chest has a role in the evaluation of pulmonary HTN in patients with suspected diffuse lung disease, eg (COPD, interstitial lung disease). Axial contrast-enhanced CT image obtained with lung window settings shows severe emphysema with loss of lung parenchyma, contributors to pulmonary hypertension.

CT of Pulmonary HTN with Thrombus CTEPH1/3 CTEPH in a 59-year-old man with a systolic pulmonary artery pressure of 100 mm Hg. Axial contrast-enhanced CT scan shows a thrombotic mass (straight arrows) in the right main pulmonary artery, an intraluminal web (curved arrow) in the left lower lobe pulmonary artery, and bronchial artery collateral vessels (arrowheads).

CT of Pulmonary HTN with Thrombus CTEPH2/3 Coronal reformatted image from contrast-enhanced CT more clearly depicts collateral vessels (arrow).

CT of Pulmonary HTN with Thrombus CTEPH3/3 Axial contrast-enhanced CT scan shows a wall-adherent soft tissue mass (arrow) in the right atrium, a finding that was confirmed to be a thrombus at pulmonary thromboendarterectomy.

Echocardiography

It’s performed to estimate the pulmonary artery systolic pressure and to assess right ventricular size, thickness, and function. In addition, echocardiography can evaluate right atrial size, left ventricular systolic and diastolic function, and valve function, while detecting pericardial effusions and intracardiac shunts. Echocardiography uses Doppler ultrasound to estimate the pulmonary artery systolic pressure. This technique takes advantage of the tricuspid regurgitation that usually exists. The maximum tricuspid regurgitant jet velocity is recorded and the pulmonary artery systolic pressure (PASP) is then calculated: PASP = (4 x [TRV] 2 ) + RAP

Echocardiography Main findings are : 1.Right ventricular enlargement (RVE). 2.Right ventricular hypertrophy (RVH). 3.Right atrial enlargement (RAE). 4.Functional tricuspid regurgitation (TR) with a high velocity regurgitant jet by Doppler (TR jet), and a mid-systolic notch on the pulmonary artery Doppler flow tracing (PA flow). 5.The interventricular septum is shifted toward the left ventricular cavity.

Echocardiography Panel A: Apical four-chamber view from a patient with severe idiopathic pulmonary arterial hypertension associated with tricuspid regurgitation. There is a large apex-forming right ventricle (RV), large right atrium (RA), and small left ventricle (LV) and left atrium (LA). Panel B: Agitated saline contrast is injected intravenously and results in RA and RV opacification; four bubbles are seen in the LV (arrow), possibly due to right-to-left flow across a patent foramen ovale.

Echocardiography Panel C shows an apical four chamber view from a patient with a large left-to- right shunt due to an atrial septal defect (ASD). The RV is apex-forming but the RV and RA are not as large as in panel A. Panel D: Contrast is injected intravenously and a few bubbles are seen in the LV; more importantly, there is a prominent negative contrast (nc) effect due to opacified atrial blood.

Echocardiography Two-dimensional echocardiogram (parasternal short axis view at the level of the aortic valve) with color flow Doppler shows significant left to right atrial flow through two atrial septal defects.

Echocardiography The apical four chamber view from a 2-D echocardiogram with color flow Doppler shows a small muscular ventricular septal defect (VSD) associated with left to right shunting of blood.

Echocardiography The short axis view from a 2-D echocardiogram shows significant right ventricular pressure and volume overload as a result of pulmonary hypertension.

Echocardiography The short axis view from a 2-D echocardiogram shows significant right ventricular pressure and volume overload as a result of pulmonary hypertension.

Echocardiography The short axis view at the level of the mitral chordae from a patient with advanced pulmonary hypertension shows substantial morphologic changes, including severe hypertrophy of the right ventricular (RV) wall, dilation of the RV chamber and hypertrophy of the right side of the septum. The septum is flattened, strongly suggesting pressure overload in the RV; this septal shape imparts a "D shape" to the left ventricle (LV) which has relatively thin walls.

Echocardiography The four chamber view from a 2-D echocardiogram with color flow Doppler shows significant tricuspid regurgitation with a dilated right atrium. There is a prosthetic mitral valve suggesting that the etiology for tricuspid regurgitation is pulmonary hypertension resulting from previous mitral valve disease.

Echocardiography The four chamber view from a 2-D echocardiogram with color flow Doppler shows significant tricuspid regurgitation. There is enlargement of the left atrium and limited mobility of the mitral valve which shows doming in diastole, suggesting that tricuspid regurgitation is the result of pulmonary hypertension due to mitral stenosis.

Summary By the time the diagnosis of pulmonary arterial hypertension is made, 90% of patients have an abnormal chest radiograph. Not specific nor sensitive. Main findings: 1.Enlarged right ventricle. 2.Enlarged right atrium. 3.Enlarged pulmonary vessels.

Summary CTPA is for the anatomic detail of the pulmonary vasculature. CTPA is the best method for demonstrating emboli. HRCT is for associated with lung diseases. Findings may be cardiac, vascular extra- cardiac, and parenchymal.

Summary On echocardiography: 1.Right atrial and ventricular enlargement. 2.Paradoxical movement of the interventricular Septum 3. Tricuspid regurgitation. Doppler echocardiography is the most reliable noninvasive method for estimating pulmonary artery pressure.

Sources 1-Pulmonary Hypertension Imaging. Author: Davinder Jassal; Chief Editor: Eugene C Lin, MD. 2-Pulmonary hypertension by Dr Yuranga Weerakkody and Dr Frank Gaillard et al.Dr Yuranga WeerakkodyDr Frank Gaillard 3-CT Findings in Diseases Associated with Pulmonary Hypertension: A Current Review Claudia Grosse, MD, and, Alexandra Grosse, MD 4-Clinical features and diagnosis of pulmonary hypertension in adults Author Lewis J Rubin, MD William Hopkins, MD Author Lewis J Rubin, MD William Hopkins, MD 5-Pulmonary hypertension in the elderly, part 1: Evaluation: Page 8 of 11 By Cynthia L. Bone-larson, MD, PhD and Kevin M. Chan, MD 6-CARDIOLOGY X-RAY QUIZ 9 By Prof. Dr. Johnson Francis, MD, DM, FACC, FRCP Edin, FRCP London